A known electrophotographic image forming apparatus such as a laser printer or an LED printer includes a drum cartridge. The drum cartridge includes a plurality of photosensitive drums. A plurality of toner cartridges are detachably attachable to such a drum cartridge. In a state where a toner cartridge is attached to the drum cartridge, a circumferential surface of a developing roller of the toner cartridge contacts a circumferential surface of a corresponding photosensitive drum of the drum cartridge.